Prescription opioid analgesics rapidly change the human brain

Pain, 05/03/2011Younger JW et al.

The results add to a growing body of literature showing that opioid exposure causes structural and functional changes in reward– and affect–processing circuitry. Morphologic changes occur rapidly in humans during new exposure to prescription opioid analgesics.

Methods

High–resolution anatomical images of the brain were acquired immediately before and after the morphine administration period

Results

Regional changes in gray matter volume were assessed on the whole brain using tensor–based morphometry, and those significant regional changes were then independently tested for correlation with morphine dosage

Thirteen regions evidenced significant volumetric change, and degree of change in several of the regions was correlated with morphine dosage

Dosage–correlated volumetric decrease was observed primarily in the right amygdala

Dosage–correlated volumetric increase was seen in the right hypothalamus, left inferior frontal gyrus, right ventral posterior cingulate, and right caudal pons

Follow–up scans that were conducted an average of 4.7months after cessation of opioids demonstrated many of the morphine–induced changes to be persistent.

In a separate study, 9 individuals consuming blinded placebo capsules for 6weeks evidenced no significant morphologic changes over time